The debate over the Anthropocene, explained

outside of Toronto in Canada is the tiny Crawford Lake it's a rare body of water known as a meromictic lake for its small size at roughly 270 M across it is deep at 23 M that means the side slop dramatically downwards and the water at the bottom doesn't mix with the water at the top making the sediment underneath extraordinarily well preserved it's this unique quality that attracted scientists in 2023 to dig up a sediment sample from the lake this core sample contain Clues to centuries of human history and they hoped it would answer a big question had humans created such a profound impact on our planet that it had created a new phase in geologic time are we now living in what some scientists call the anthropos there's actually an official Global body of scientists whose job it is to decide this question the international Commission on rraphy or IC Phil Gibbard is a part of it and our remit is to actually control the stratigraphy of the entire planet really that means the entire geological column starting with the formation of the Earth right up to the present day they are the guardians of the geologic calendar of the Earth's 4.6 billion year history geologic time has different types of Divisions these are eons that span hundreds of millions of years then there are eras periods epochs and stages we are living here in the roughly 12,000-year hallene Epoch this is where the anthropos would start not as an era but an Epoch this system of organization is based in part on the fossil record which tells the story of huge changes on earth like the explosion of animal fossils that Mark the start of the Cambrian Period the chemical makeup of rocks can give signals too like the idium left behind by the asteroid that wiped out non-avian dinosaurs which marks the start of the paleogene period or the way the Earth's magnetism is recorded in rock layers that signal major events like the large volcanic eruption that started the chadian stage roughly 28 million years ago it was in the year 2000 that an academic essay proposed the idea of formalizing the anthropos its name is two components to it the anthropos is obviously the human part of it the scene is relates to the fact it would be a Epoch of the scoic which is the last 66 million years since the asteroid impact wiped out the dinosaurs in the view that we' moved away from what might be deemed to be the normal conditions of the holline inter glacial which is a warm period in the Ice Age which began 12,000 years ago and we moved away from that because of the consequence of human activity the best rock evidence that exists anywhere in the world to Mark a division in time scale is called a golden spike and scientists stick and actual golden spike in the ground where they find it that means that while there are numerous fossils for an extinct species called a kodon around the world from the oriv visian period a single exceptional one from New Finland officially marks the start of the period if there's ever a question over a boundary the IC deploys one of their 15 subcommittees Each of which specializes in a single time period these subc committies will set up a working group of scientists from around the world to identify a golden spike Phil Gard set up the anthropos working group so it was set up within the quater subcommission to assess the possibility of an anthropos Epoch Earl Ellis joined the anthropos working group in 2009 2 years later Colin Waters joint the first goal we had was to plow through lots and lots of data sets Publications by many other research groups to see if there was evidence in geological strata such as lakes in the oceans in repete successions corals even cave deposits where you could record the anthropos and increasingly we saw that there was evidence of of changes happening the problem is the evidence of human impact on Earth is spread over hundreds if not thousands of years and the working group needed to decide when the anthropos scene started the authors of the 2000 paper had suggested its start at the Industrial Revolution which not everyone agreed with my tendency was more toward the early AG cultural transformations of the planet but events like the emergence of Agriculture took place slowly and more importantly regionally agriculture was off the table pretty quickly and that's also why the Industrial Revolution came off the list the group decided they'd have the best chance of convincing the IC if they focused on the most dramatic moment of change possible and so they chose the great acceleration because it was considered to be the equivalent of this kind of instantaneous Global change great acceleration greatly increased industrialization which followed upon the second world war appearance of Novel materials Plastics is probably the most famous of those going into production and then being dispersed across the planet geochemical signals to do with burning of fossil fuels introduction of artificial fertilizers for agriculture changing the nitrogen cycle how humans have increased the rate of extinctions how we've managed to move so many species of plants and animals across the planet next the group had to for their Golden Spike the physical sample that best showed a change had occurred they researched 12 different sites around the world from coral reefs to peep bogs to ice sheets which brought them to Crawford Lake because of the unique qualities of Crawford Lake the sample has clear annual rings of sediment layers dating back to the 1300s where corn dust shows evidence of indigenous agricultural activity then thick nitrogen Rich layers show the arrival of European settlers who logged in farmed the surrounding area in the 1930s there's evidence of the dustow and around 1950 they found what they were looking for plutonium from the first hydrogen bomb [Music] test one of those points of time you can correlate very precisely is the onset of detonations of these nuclear weapons because they they they produce a global signal so you can correlate those across the planet all but one of the 12 samples the working group found throughout the world had evident of nuclear fallout from bomb testing of that era nuclear weapons testing isn't necessarily the best evidence for how humans have changed the planet but it is the clearest most universal signal they could find it's not strange that they chose the nuclear signal because it's a very good signal for the current time in that Lake in 2023 the anthropos working group submitted the 12 sites with the Crawford Lake proposal as the golden spike to the quinary subcommittee for a vote and the voting members rejected it many IC members thought the addition of a roughly 70-year-old Epoch at the end of the holos scene was too insignificant relative to the enormity of Earth's geologic history we can't see the word for the trees you know in geological terms something that lasted less than a century would just be a blip a blink of an eye in a geological record Earl Ellis resigned from the working group prior to the vote partly because he disagreed there had to be a single narrow definition of the anth the idea that significant transformation of the planet occurred with the onset of the anthropos scene and not before that was one of my reasons for resigning the anthropos scene is about understanding that humans are transforming this planet and that should be the focus not 1952 in Crawford Lake and Colin Waters maintains the anthropos legitimacy it's quite amazing how humans have managed to modify the planet so profoundly in less than 70 years probably the only equivalent I can think of is the asteroid impact at the end of the Cretaceous that wiped out the non-avian Dinosaurs the IC decision doesn't deny that humans have impacted the planet just that it doesn't yet have a place in geologic time for now it's still a term that's found cultural resonance as we grapple with our mark on Earth if humans are still around in hundreds or thousands of years maybe our future descendants will have the perspective to identify our species Golden Spike the field of geologic Strat graphy is meant for deciphering the Earth's deep history Millions if not billions of years ago through the only means available to us decoding the science and rock fragments around the world it's an awkward fit for litigating our modern history after all we don't have to look to the Rock record to show us the impact humans have had the evidence for that is abundant and it speaks for itself we don't need to create a break in time to understand that this is the time when humans are transforming the planet thanks for watching a big part of the story is about how scientists interpret data and as Vox producers we're constantly thinking about ways to analyze and visualize data for our stories if you're interested in learning a skill like data analysis a great place to start is brilliant our sponsor for this video brilliant is a learning platform with 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Channel: Vox

Views: 978,101

Keywords: Vox.com, anthropocene, climate change, environment, explain, explainer, geology, science, stratigraphy

Id: Oh2RevEsyoI

Length: 9min 43sec (583 seconds)

Published: Fri May 03 2024